Fluid-blast circuit interrupter having serially-related pressure-generating and interrupting arcs



3,259,724 RELATED July 5, 1966 w. s. ASPEY ET AL FLUID-BLAST CIRCUIT INTERRUPTER HAVING SERIALLY PRESSURE-GENERATING AND INTERRUPTING ARCS Original Filed Aug. 27, 1959 6 Sheets-Sheet l July 5, 1966 w. s. ASPEY ET AL 3,259,724

FLUID-BLAST CIRCUIT INTERRUPTER HAVING 'SERIALLY-RELATED PRESSURE-GENERATING AND INTERRUPTING ARCS Original Filed Aug. 27, 1959 6 Sheets-Sheet 2 Fig.3.

July 5, 1966 w, s, As Y ET AL 3,259,724

FLUID-BLAST CIRCUIT INTERRU ER HAV SERIALLY-RELATED P SURE- ENERATING AND INTE PTING ARCS Original Filed Aug. 1959 6 Sheets-Sheet 3 July 5, 1966 w. s. ASPEY ET AL 3,259,724

FLUID-BLAST CIRCUIT INTERRUPTER HAVING SERIALLY-RELATED PRESSURE-GENERATING AND INTERRUPTIN G ARCS 6 Sheets-Sheet 4 Original Filed Aug. 27, 1959 Fig.4B.

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FLUID-BLAST CIRCUIT INTERRUPTER HAVING SERIALLY-RELATED PRESSURE-GENERATING AND INTERRUPTING ARCS Original Filed Aug. 27, 1959 6 Sheets-Sheet 5 Fig.5.

Liquid Level July 5, 1966 w s. ASPEY ET AL 3,259,724 Q FLUID-BLAST CIRCUITENTERRUPTER HAVING SERIALLY-RELATED PRESSURE-GENERATING AND INTERRUPTING ARCS Original Filed Aug. 27, 1959 6 Sheets-Sheet 6 Fig.6.

United States Patent '"ice FLUID-BLAST CIRCUIT INTERRUPTER HAVING SERIALLY-RELATED PRESSURE-GENERATING AND INTERRUPTING ARCS Wayne S. Aspey, Monroeville, Pa., and Ben amin P. Baker, deceased, late of Monroeville, Pa., by Mellon National Bank & Trust Co., executor, assrgnors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Original application Aug. 27, 1959, Ser. No. 836,405, now Patent No. 3,110,791, dated Nov. 12, 1963. Divided and this application Nov. 5, 1962, Ser. No. 235,573

6 Claims. (Cl. 200148) This invention relates to circuit interrupters in general, and more particularly to improved arc-extinguishing structures and contact-operating mechanisms therefor.

This application is a division of our application filed August 27, 1959, Serial No. 836,405, issued November 12, 1963, as U.S. Patent 3,110,791, and assigned to the assignee of the instant application.

In United States patent application, Serial No. 683,760, filed September 13, 1957, now US. Patent 3,150,245, issued September 22, 1964 to Benjamin P. Baker and Winthrop M. Leeds, and assigned to the assignee of the instant application, there are disclosed and claimed improved arc-extinguishing structures, particularly adapted for the utilization of liquefied gases. It is a general object of the present invention to improve upon the arcextinguishing structures set forth in the aforesaid patent application, particularly adapting them for higher-voltage and higher-current applications.

Another object of the present invention is to provide an improved circuit interrupter, particularly adapted for the employment of liquefied gas, in which the enclose-d volume for the liquefied gas is a minimum, yet ensuring adequate spacing distances between parts of opposite potential to prevent breakdown.

Another object of the present invention is to provide improved arc-extinguishing structures particularly adapted for series connection, each of said arc-extinguishing structures being of the unit, or elemental type, and of improved construction.

Still a further object of the present invention is to provide an improved circuit-interrupting structure, involving a multiplicity of serially related contact gaps and employing an improved, simple and highly effective contact-operating arrangement.

Another object of the present invention is to provide an improved circuit-interrupting structure in which inspection and maintenance may readily be achieved.

Still a further object of the present invention is to provide an improved circuit-interrupting structure in which a radial magnetic field is utilized, in a simplified manner,

to provide a rotation of the arc column between the separable contacts, to result in more etficient contact of the arc with the arc-extinguishing medium.

Another object of the present invention is to provide an improved circuit-interrupting structure involving a pair of serially related pressure-generating arcs, in series with a pair of serially related interrupting arcs.

Another object of the present invention is to provide an improved circuit-interrupting structure involving a pair of terminal bushings extending into a metallic enclosure, in which the capacitance employed in conjunction with the terminal bushings is utilized for dividing the voltage between the series contact arrangements in the open-circuit position of the interrupter.

Another object of the present invention is to provide improved contact-operating arrangements for circuitinterrupting devices.

3,259,724 Patented July 5, 1966 Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIGURE 1 is a side elevational view, partially in vertical section, of a circuit-interrupting device embodying the principles of our invention, with the contact structure being shown in the closed-circuit position;

FIG. 2 is a fragmentary, vertical sectional view, taken substantially along the line II-II of FIG. 1, looking in the direction of the arrows, again the contact structure being shown in the closed-circuit position;

FIG. 2A is a fragmentary plan view of the bifurcated operating lever employed for effecting reciprocating motion of the operating-rod assembly;

FIG. 3 is a considerably enlarged, fragmentary, vertical sectional view showing one type of interrupting construction, which may be employed within the tank structure of 'FIG. 1, with the contact structure being illustrated in the closed-circuit position;

FIGS. 4A and 4 B collectively illustrate a vertical sectional view taken through a modified type of circuitinterrupting structure employing a two-break device, with the contact structure being illustrated in the closed-circuit position;

FIG. 5 illustrates a fragmentary, vertical sectional View taken through a further modified type of circuit-interrupting structure, the contact structure being illustrated in the open-circuit position;

FIG. 6 illustrates a side elevational view through a modified type of circuit-interrupting assemblage, illustrating how :a pair of serially related arc-extinguishing units may be enclosed, and simultaneously operated, the contact structure being illustrated in the open-circuit position.

Referring to the drawings, and more particularly to FIGS. 1 and 2 thereof, the reference numeral 1 generally designates a circuit-interrupting assemblage including, generally, a terminal bushing 2, a live tank structure at high potential 3, an insulating support 3A, and an operating-mechanism compartment 4.

Generally, the circuit through the interrupting assemblage 1 includes the upper line-terminal connection 5, constituting the upper outer extremity of the terminal stud extending axially through the terminal bushing 2, a slotted, stationary, finger assembly 6, a conducting guide rod 7 (which makes sliding contact with the fingers 6), through an arc-extinguishing unit, generally designated by the reference numeral 8, to a lower line-terminal connection 9.

With reference to FIG. 3, which shows more clearly the arc-extinguishing unit 8, it will be noted that a vented, tubular contact 10 reciprocally moves in a vertical direction, making separable engagement with a plurality of relatively stationary finger contacts 11, the latter being biased radially inwardly by a plurality of compression springs 12. In the particular arc-extinguishing unit shown in FIG. 3, by way of example, there are eight finger contacts 11 and a corresponding number of contact-bias ing springs 12.

With reference to FIG. 1, it will be noted that the reciprocally movable, tubular, venting contact 10 constitutes the lower extremity of the movable contact assemblage 13, comprising the movable contact 10, a crosshead or yoke structure 14, and a pair of upwardly extending insulating operating rods 15. As shown more clearly in FIG. 2, the lower ends of the insulating operating rods 15 have secured thereto metallic rod ends 1501,

10, separating the latter from the relatively stationary thereby conducts the current through the terminal bushing 2.

Any suitable mechanism may be employed within the mechanism compartment 4 to effect rotation of an operating shaft 17, which extends externally of the mechanism compartment, or cell 4. Pivotally connected, by a pin 18, to the free end of an operating crank 19, keyed to the operating shaft 17, is an operating rod 22.

The lower end of the operating rod 22 extends within compression accelerating spring 24. The lower end of the compression accelerating spring 24 seats upon a fixed spring base 25, which is secured to the mechanism housing 4. Carried by the operating rod 22 is a washer 26, which provides the upper seat for the accelerating spring 24. As a result, downward closing movement of the operating rod 22 will effect compression of the accelerating spring 24.

The upper end of the operating rod 22 has an insulating portion 22a which is pivotally connected, as at 27, to an operating crank-arm 28, having a bifurcated end portion 29 clamped, by a bolt 30, to an operating shaft 31, which extends through the side wall of a laterally extending offset portion 3a of the tank structure 3 to effect opening and closing movement of the movable contact assembly 13 disposed therewithin.

With reference to FIG. 2A, it will be noted that this transmission of motion is effected by a crank-arm. 32, clamped to the operating shaft 31, and having a bifurcated portion 33 including a pair of arms 34. The arms 34 are pivotally connected, as at 35, to upper bifurcated portions 36 (FIG. 2) constituting the upper extremities of the insulating operating rods 15.

To limit the rotation of the operating crank-arm 28, bumper stops 37 and 38 are provided attached to the side mechanism compartment 3a. Also a shock absorber 39 is pivotally mounted at one end 40 to a lug, not shown, welded to a side of the tank 3. As shown in FIG. 1, the left-hand end of the shock absorber 39 is pivotally connected to the free end of the operating crank 28 by a pivot pin 41.

A liquid-gauge structure 42 (FIG. 2), including a glass tube 43, is provided so that the level of the liquid within the tank structure 3 may be measured.

From the foregoing description, it will be apparent that counter-clockwise rotation of the operating shaft 17, as effected by any suitable mechanism disposed interiorly within the operating cell 4, will, through the linkage, effect compression of the accelerating spring 24, and corresponding clockwise rotation of the crank-arm 28. The clockwise rotation of the crank-arm 28 will effect corresponding clockwise rotation of the internally disposed operating crank 32, effecting downward closing motion of the movable contact assembly 13 including the movable contact 10.

To effect opening of the circuit interrupter, the mechanism, disposed interiorly within the operating cell 4 is tripped, or unlatched, thereby permitting the accelerating spring 24 to force the operating crank 28 in a counterclockwise direct-ion, as viewed in FIG. 1, effecting corresponding counter-clockwise rotation of the interiorly disposed operating crank 32, and moving the movable contact assembly 13 upwardly effecting separation between the movable contact and the stationary contacts 11.

Referring to FIG. 3, it will be observed that the plurality of relatively stationary finger contacts 11 are disposed within a support ring 44, which is bolted, by bolts 45,

v to a contact or interrupter support 46. The contact support 46, in turn, is bolted, by bolts 47, to a mounting flange ring 48, which is welded, as at 49, to the lower extremity of the tank 3. An opening 50 is provided through the lower contact support 46. This opening 50 is normally closed by a plug 51.

Fixedly secured by the bolts 45 to the interrupter support 46 is an orifice support 52 composed of insulating material, and having a lower mounting flange portion 52a. Lining the orifice support 52 is a sleeve 53 and an orifice ring 54, both composed of polytetrafluoroethylene, as more fully explained in United States Patent 2,757,261.

It will be noted that vents are provided adjacent the upper end of the tubular movable contact 10. A relatively stationary plug-type arcing horn 56 is provided, being secured to the support ring 44 by a mounting bolt 57.

The manner of operation of the interrupting structure 8 will now be described. During the opening operation, the movable tubular contact 10 is withdrawn upwardly by the movable contact assembly 13 in the manner previously described. This causes separation between the lower contacting portion 10a of movable contact 10 and the fingers 11. The established arc is drawn between an arc-resisting ring 59, secured by a press fit to the lower end of the movable contact 10 and the upper end 56a of the arcing horn 56. The liquefied gas 60, disposed within the tank 3, and filling the region 61 within the orifice support 52 is gasified, and the pressure within the region 61 is considerably increased. Upon the upward withdrawing of the movable tubular venting contact 10 out of the orifice restriction 62 of the orifice ring 54, the

generated gas and liquid particles will be directed into the arc stream, not shown, and effect the extinction thereof. Because of the provision of the venting apertures 55 in the tubular movable contact 10, an exhausting of gas will take place upwardly through the movable tubular contact 10 prior to the withdrawal thereof through the orifice restriction 62, as indicated by the arrows 63.

Using liquid SP the interrupter 8 gave satisfactory results at 6'6, 44, and 22 kv. to currents of 2000 amps. Later tests showed good results from 25,000 to 50,000 amperes.

The liquid-gauge structure 42 (FIG. 2) indicates the proper level of the liquefied gas, which is preferably above the orifice structure 63 near the level 64, for example.

FIGS. 4A and 4B collectively illustrate a modification ofthe invention, in which a modified type of interrupting structure, generally designated by the reference numeral 66, is substituted for the interrupting structure 8 of FIG. 7

3. As before, a yoke or cross-head structure 14 is provided, being pivotally connected to the operating rods 15 by pivot pins 16. The movable tubular venting contact 10, with its venting apertures 55 at the upper end thereof, is similar in structure, and operation to the movable contact 10 of FIG. 3. With reference to FIG. 413, it will be noted that the movable contact 10 makes abutting engagement with an intermediate contact, generally designated by the reference numeral 67. The lower end 67a of the intermediate contact 67 makes contacting engagement with a lower, relatively stationary plug-type pressure-generating contact 68. Bolts 47 fixedly secure an interrupter support 69 to a mounting flange ring 48, the latter being secured, as by welding 49, to the lower end of the metallic tank 3. A cylindrical insulating tank liner 70 is disposed within the tank 3 along the inner wall thereof, and has the function of protecting the tank 3 from the effects of arcing during the opening operation of the interrupter 66.

Additional stud bolts 71 fixedly secure an orifice support 72 and an insulating mounting support 73 into position. The lower ends of the mounting stud 71 threadedly secure into tapped openings 74 provided in the interrupter support 69.

As shown in FIG. 413, a stationary support pin 75, extending laterally within an opening 76, provided in the mounting support 73, serves to limit the opening movement of the intermediate contact 67. A spring-seat plate 77 has an opening 78 therein to accommodate the stop pin 75. The spring-seat plate 77 serves as a lower spring seat for a battery of compression springs 79, 80, which extend upwardly within the interior of the tubular intermediate contact 67, and serve to bias the same in an upward opening direction. An arc-resisting tip 81, having an aperture '82 therein, is fixedly secured, by any suitable means, to the upper end 67b of the intermediate contact 67. A slot 83 in the side wall of the tubular intermediate contact 67 accommodates the stop pin 75, and cooperates therewith to limit the opening travel of the intermediate contact 67.

The orifice support 72 fixedly clamps into position an orifice ring 84 and an orifice liner 85, which, as before, may be composed of polytetrafluoroethylene. Openings 86, provided at the upper end of the orifice liner 85, register with openings 87 and axially extending bores 88, which extend upwardly within the mounting support 73. These several registered openings provide a means of communicating the pressure from the region 89, constituting a pressure-generating chamber, with the region 90, constituting an interrupting region, and disposed within the upper orifice structure, generally designated by the reference numeral 91. In addition, a radial magnetic field coil 92 is provided, comprising a few series turns of formed copper bar, which set up a radial magnetic field,

as indicated by the arrows 93, to effect a rotation of the pressure-generating are, not shown.

During the opening operation, the cross-head structure 14 effects upward opening movement of the movable tubular venting contact 10. The compression springs 79, 80 effect a following, upward travel of the intermediate contact 67. This causes a separation between the lower end 67a of the intermediate contact 67 and the stationary pressure-generating contact '68. A pressure-generating arc, not shown, is drawn, which is whirled, or rotated by the magnetic field 93, set up by the series magnetic coil 92. When the lower end of the slot 83, within intermediate contact 67, abuts stop pin 75, the upward opening movement of the intermediate contact 67 is halted. Subsequently, the upper movable tubular venting contact separates from the upper end 67b of the intermediate contact 67, to establish an interrupting arc, not shown, which is extinguished by a plurality of radially directed fluid jets traveling upwardly from the pressure-generating region 89 through the axial bores 88, within mounting support 73, and radially inwardly through the plurality of openings 86 in orifice liner 85. As a result of the fluid forced upwardly from the pressure-generating chamber 89 by the establishment of pressure resulting from the pressure-generating arc, the interrupting arc is quickly extinguished. -In addition, fluid is exhausted upwardly within the interior of the movable tubular contact 10, as indicated by the arrows 94. The effect is very rapid arc extinction.

During the closing operation, the cross-head structure 14 is moved downwardly by the operating rods 15. This effects downward closing travel of the movable tubular contact 10, which strikes the intermediate contact 67 and forces the latter downwardly into engagement with the .stationary contact 68, compressing the springs 79, 80.

The circuit is then closed. This interrupter 66 interrupted currents over 50,000 amps. at 66, 44, and 22 kv.

In the modified interrupter 96 of FIG. 5, it will be noted that the movable tubular venting contact 10 makes engagement with a plurality of contact fingers 97. The contact .fingers 97 are formed by suitably machining, and slotting helically grooved surface 102. The helical grooves 103 compel the current to flow within the helically extending thickened portions 104, constituting turns of a radial magnetic-field coil, generally designated by the reference numeral 105. This radial magnetic field coil constitutes the upper part of a tubular contact support 106, having a radially outwardly extending mounting flange portion 107, which is maintained in position by a mounting ring 108, secured by a plurality of mounting bolts 109 to an interrupter support plate 110. As before, the interrupter support plate 110 is secured by bolts 47 to a mounting flange ring 48 welded, as at 49, to the lower end of the tank 3. A mounting ring 111 is secured by bolts 112 to the interrupter support plate 110. Immediately above the support ring 111 are three insulating rings 113-115, which are secured by mounting bolts 116, the latter threaded into tapped openings 117 provided in the support ring 111.

An insulating orifice ring 118 is secured into place by a split mounting ring 119, the latter having a flanged portion 120 cooperating with a mounting ring 121. The mounting ring 121 is secured by bolts 122 fixedly into position, as shown in FIG. 5.

During the opening operation, the movable tubular vented contact 10 moves upwardly, as described herei-nbefore, causing the separation of the lower ring-shaped arc-resisting, tip portion 59 from the plug contact 99 and fingers 97. The compression spring 100 effects upward following motion of the plug contact 99 with the movable tubular contact 10. An arc, not shown, is drawn, and causes the radial magnetic field-coil structure 105 to carry the series current through the thickened portions 104, or turns thereof, to effect the setting up of a radial magnetic field. This radial magnetic field, as indicated by the arrows 123, effects the rotation of the established arc around the upper annular ring portion 124 of the field-coil structure 105. Meanwhile, the establishment of pressure, generated by the heat of the are drawn through the orifice restriction 125, effects extinction of the are established therethrough.

During the closing operation, the movable contact 10 moves downwardly, and passes through the restriction 125 engaging the plug contact 99 and the finger contacts 97.

The circuit is then closed through the interrupter.

The interrupting assemblage 128 in FIG. 6 shows how a pair of arc-extinguishing units 8, 66, or 96 may be simultaneously operated. As shown in FIG. 6, a support base 129 supports upwardly a cylindrical, grounded, metallic casing 130, having inspection covers 131. Extending downwardly interiorly through the upper ends 132 of the metallic casings is a pair of terminal bushings 133. Line connections 134, 135 may be provided.

A pair of hollow tubes 136, 137 laterally connect the metallic casings 130. The lower metallic tube 137 not only has interiorly extending therewithin the bar connector 138, connecting the interrupting units 8, but also provides a support 139 for a pair of crank-arms 140, 141. The crank-arms 140, 141 are keyed to an operating'shaft 142. Rotation of the crank-arm effects reciprocal vertical movement of a connecting link 143, the upper end of which is pivotally connected to a crank-arm 144, which effects the rotation of an operating shaft 145, extending interiorly Within a downwardly depending housing structure 146. Interiorly of the housing structure 146 is another crank-arm 147, which drives, at its free end, a pair of links 148, which are pivotally connected to crank-arms 149. The outer free ends of the crank-arms 149 are pivotally connected, as at 150, to the operating rods 15. The operating rods 15 are connected to the cross-head structure 14, as more clearly shown in FIG. 2 of the drawings.

The circuit interrupting assemblage 128 illustrated in FIG. 6 shows how a pair of arc-extinguishing units 8 may be simultaneously operated, by a contact-operating mechaadequate protection for operating personnel is aiforded. The arc-extinguishing units 8 may be fixedly secured into place by insulating mounting pedestals 152, as shown. A horizontally extending operating rod 133, pivotally connected to the crank-arm 141, effects rotation of the operating shaft 142. The operating shaft 142 effects through the crank-arm 140 and link 143, rotation of the crank arm 144. Rotation of the crank-arm 144 eliects rotation of the operating shaft 145, and transmits the operating energy interiorly of the housing structure 146. The crank-arm 147, keyed to the operating shaft 145, effects simultaneous motion of the links 14-8, which effect pivotal rotation of the crank-arms 149. The crank-arms 149 efiFect opening and closing motion of the operating rods 15 and crosshead structure 14, in the manner as described hereinbefore.

From the foregoing description of the invention, it will be apparent that there is provided a number of interrupting structures particularly suitable for the liquefied gases as set forth in the aforesaid Leeds and Baker application. Although the interrupting structures have particular advantage when used with a liquefied gas, it is to be noted that a certain degree ott interrupting etfectiveness is also available by using the same interrupting structures with a suitable ordinary arc-extinguishing fluid, such as a liquid, for example, circuit-breaker oil.

From the foregoing description of the present invention, it will be apparent that there are disclosed novel types of circuit interrupters utilizing liquefied gas injected into the arcing zone. Although liquefied SP has been used as an example of a possible liquefied gas, in describing the structures, it is to be clearly understood that liquefied selenium hexafiuoride, or any one or a mixture of two or more of liquefied gases enumerated below may 'be employed in the substitution of liquid SF The gases which are suitable for use in interrupters of the type considered, have similar properties and characteristics as set out in the fol-lowing table.

Although the foregoing liquefied gases may be used to advantage, exceptional and unusual performance is obtained with liquid SE, and liquid Se'F since the gaseous phase of these two materials are so highly etfective in arc interruption and high dielectric insulation.

Although there have been shown and described specific structures, it is to be clearly understood that the same were merely (for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

We claim as our invention:

1. The combination in a circuit interrupter of a relatively stationary contact, a movable tubular intermediate contact having a substantially closed end portion, and .a movable interrupting contact all making end-toend engagement in the closed circuit position of the interrupter, an opening spring disposed interiorly of the tubular intermediate contact, a relatively stationary spring seat disposed interiorly of the movable tubular intermediate contact and serving as a spring seat for said opening 8 spring, a slot in the side wall of the movable tubular intermediate contact, a relatively stationary support member extending through said slot and stationarily supporting said relatively stationary spring seat, the movable tubular intermediate contact being moved by said opening spring away from the relatively stationary contact to establish a pressure-generating arc, the movable interrupting contact separating from the movable tubular intermediate contact to establish another serially related interrupting arc during the opening operation of the interrupter following abutting contact of said relatively stationary support member with the end of the slot, means defining orifice means for facilitating interruption of said interrupting arc, supporting means for supporting said orifice means and containing fluid-passage means communicating radially inwardly with the upstream side of said orifice means, and restricting guide means for slidably guiding opening motion of said intermediate contact and compelling substantially all the fluid to flow under pressure from the pressure-generating are through said fiuid-passage means for extinguishing said interrupting are.

2. The combination in a circuit interrupter of a relatively stationary contact, a movable tubular intermediate contact having a substantially closed end portion, and a movable interrupting contact all making end-to-end engagement in the closed-circuit position of the interrupter, an opening spring disposed interiorly of the tubular intermediate contact, a relatively stationary spring seat disposed interiorly of the movable tubular intermediate contact and serving as a spring seat for said opening spring, a slot in the side wall of the movable tubular intermediate contact, a relatively stationary support member extending through said slot and stationarily supporting said relatively stationary spring seat, the movable tubular intermediate contact being moved by said opening spring away from the relatively stationary contact to establish a pressure-generating arc, the movable interrupting contact separating from the movable tubular intermediate contact to establish another serially related interrupting arc during the opening operation of the interrupter following abutting contact of said relatively stationary support member with the end of the slot, a series radial magnetic field coil associated with the relatively stationary contact to establish a radial magnetic field, the end of the intermediate contact cooperating with the relatively stationary contact being open so that the rotating arc may move around the annular contact surface of the open end of the intermediate contact, means defining orifice means for facilitating interruption of said interrupting arc, supporting means for supporting said orifice means and containing fluid-passage means communicating radially inwardly with the upstream side otf said orifice means, and restricting guide means for slidably guiding opening motion of said intermediate cont-act and compelling substantially all the fluid to flow under pressure from the pressure-generating are through said fluid-passage means for extinguishing said interrupting arc.

3. The combination according to claim .1, wherein the fluid-passage means comprises a plurality of circumferentially-disposed spaced bores extending generally parallel to the direction of movement of the movable interrupting contact.

4. The combination according to claim 3, wherein a series radial magnetic field coil is associated with the relatively stationary contact to elfect rotation of the pressure-generating arc.

5. A liquefied-gas circuit interrupter including a generally cy'lindrically-shaped metallic tank, an interrupting unit disposed within the metallic tank and supported at one end thereof, an interrupter support plateedetachably secured to one end of the tank to close the same and serving to support the interrupting unit, a relatively stationary contact secured to said interrupter support plate, a generally cylindrically-shaped mounting member formed of insulating material and having a plurality of spaced axially extending fluid bores provided therein, a tubular intermediate contact disposed within said generally cylindrically-shaped mounting member and having a substantially closed end portion, a biasing spring disposed interiorly of said tubular intermediate contact to bias the same away from the relatively stationary contact, an orifice member having an orifice opening, a movable interrupting contact movable through said orifice opening and into contacting engagement with the intermediate contact in the closed-circuit position, said fluid bores communicating at one end with the pressure-generating region adjacent the relatively stationary and intermediate contacts, the other ends of the fluid bores communicating with the interrupting region on the upstream side of said orifice member, the pressure-generating are established between the relatively stationary and intermediate cntacts forcing fluid through said fluid bores and into the interrupting arc established between the intermediate and movable interrupting contacts, said mounting member providing a restricted guide for said intermediate contact, and liquefied gas covering the interrupting unit.

6. A liquefied-gas circuit interrupter including a generally cylindrically-shaped metallic tank, an interrupting unit disposed within the metallic tank and-supported at one end thereof, an interrupter support plate detachably secured to one end of the tank to close the same and serving to suppont the interrupting unit, a relatively stationary contact secured to said interrupter support plate, a generally cylindrically-shaped mounting member formed of insulating material and having a plurality of spaced axially extending fluid bores provided therein, a tubular intermediate contact disposed within said generally cylindrically-shaped mounting member and having a substantially closed end portion, a biasing spring disposed interiorly of said tubular intermediate contact to bias the same away from the relatively stationary contact, an

orifice member having an orifice opening, a movable interrupting contact movable through said orifice opening and into contacting engagement with the intermediate contact in the closed-circuit position, said fluid bores cornmunicating at one end with the pressure-generating region adjacent the relatively stationary and intermediate contacts, the other ends of the fluid bores communicating with the interrupting region on the upstream side of said orifice member, the pressure-generating are established between the relatively stationary and intermediate contacts forcing fluid through said fluid bores and into the interrupting arc established between the intermediate and movable interrupting contacts, said mounting member providing a restricted guide fior said intermediate contact, liquefied gas covering the interrupting unit, and a series radial magnetic field coil associated with the relatively stationary contact to effect rotation of the pressure-generating arc.

References Cited by the Examiner UNITED STATES PATENTS 1,912,176 5/1933 Burham 200- 2,075,749 3/ 1937 Paul 200-450 2,294,801 9/ 1942 Rawlins 200-149 FOREIGN PATENTS 14,108 9/191 1 France.

741,488 12/ 1932 France.

814,479 9/ 1951" Germany.

497,612 12/ 1938 Great Britain.

KATHLEEN H. CLAF-FY, Primary Examiner.

ROBERT S. MACON, ROBERT K. SCHAEFER,

Examiners. 

1. THE COMBINATION IN A CIRCUIT INTERRUPTER OF A RELATIVELY STATIONARY CONTACT, A MOVABLE TUBULAR INTERMEDIATE CONTACT HAVING A SUBSTANTIALLY CLOSED END PORTION, AND A MOVABLE INTERRUPTING CONTACT ALL MAKING END-TOEND ENGAGEMENT IN THE CLOSED CIRCUIT POSITION OF THE INTERRUPTER, AN OPENING SPRING DISPOSED INTERIORLY OF THE TUBULAR INTERMEDIATE CONTACT, A RELATIVELY STATIONARY SPRING SEAT DISPOSED INTERIORLY OF THE MOVABLE TUBULAR INTERMEDIATE CONTACT AND SERVING AS A SPRING SEAT FOR SAID OPENING SPRING, A SLOT IN THE SIDE WALL OF THE MOVABLE TUBULAR INTERMEDIATE CONTACT, A RELATIVELY STATIONARY SUPPORT MEMBER EXTENDING THROUGH SAID SLOT AND STATIONARY SUPPORTING SAID RELATIVELY STATIONARY SPRING SEAT, THE MOVABLE TUBULAR INTERMEDIATE CONTACT BEING MOVED BY SAID OPENING SPRING AWAY FROM THE RELATIVELY STATIONARY CONTACT TO ESTABLISH A PRESSURE-GENERATING ARC, THE MOVABLE INTERRUPTING CONTACT 